In general, since a distribution apparatus provided at a distribution point in an access network is located at a place where it is difficult to connect independent power sources such as ground or manhole, the distribution apparatus operates by reversely receiving power supplied from a power supply apparatus located at an end subscriber on a network. A concept of power supply of such a scheme is called reverse power feeding (RPF).
In a network structure using the reverse power supply, the distribution point is connected with at least one customer premise (normally, four ports are generally used) and operates by receiving power from at least one customer premise.
In a standard, there is no problem with load balancing because the reverse power supply is designed based on one port, but in an actual design, since the reverse power supply is designed based on multiple (for example, four) ports, equal distribution of an electric charges for each user and an electric charge equal to the used electric charge are required.
Since all of one or more customer premises connected to the distribution point are continuously used at the same time, controlling the load balancing of the reverse power feeding is required. The reason is that when the load balancing is not properly achieved, the electricity charge charged to equipment located on each customer premise become uneven. Accordingly, a load balancing technology is introduced and used, in which electricity is evenly distributed according to a load to evenly pay the electric charge as much as the electric charge is used.
However, since the load balancing technique in the related art described above is performed almost at the distribution point, it is necessary to perform line resistance measurement for performing the load balancing whenever a use environment is changed, determination of the amount of power at each customer premise through the line resistance measurement, providing the determined amount of the power to each customer premise, and the like, and as a result, thereby making it difficult to design the distribution point.
In addition, in a case where the reverse power feeding is not properly performed from the customer premise to the distribution point, it is difficult to check the case at the distribution point. Therefore, there is a problem that it is difficult to perform the load balancing itself.
Accordingly, the present invention has been in an effort to present a reverse power feeding apparatus and a method thereof, which measure line resistance of a communication line directly connected to the distribution point at each customer premise and reflects the measured line resistance to perform power feeding to the distribution point, thereby feeding power having a capacity which is averagely almost similar to the distribution point from each customer premise.
Next, a brief description will be given of the prior art in the technical field of the present invention, and then, a technical matter which the present invention intends to differentiate from the prior art will be described.
First, U.S. Pat. No. 9,319,537 (registered on Apr. 19, 2016) is a technique for load balancing of reverse power feeding to estimate communication line power loss in a normal communication system.
A difficulty in the power feeding between the existing central office (CO) and the DP is that since a local power supply for the DP is either expensive to install or impossible to install, the power is fed not to be interrupted by data communication by configuring power source equipment (PSE) in the customer premise equipment (CPE). The CPE includes Power over Ethernet (POE) and the POE delivers power to the DP via a twisted pair. Theoretically, each CPE needs to deliver the same amount of power to the DP, but a power feeding amount of a power device (PD) is not the same due to a difference in the length of the twisted pair between the DP and the CPE. In particular, a CPE with a long twisted pair needs to provide more power than a short CPE. The prior art aims at balancing the power feeding of the CPE by configuring a power supply unit having a large number of interface ports in the DP.
However, since the present invention proposes a technical configuration for measuring the line resistance of the communication line connected to the distribution point at the customer premise and performing the reverse power feeding to the distribution point by reflecting the measured line resistance, there is a clear difference in the technical characteristics between the present invention and the prior art that proposes the technical configuration that just balances the power feeding of the CPE at the DP by configuring the power supply unit having a large number of interface ports.
Further, U.S. Pat. Registration No. 8,897,431 (registered on Nov. 25, 2014), which relates to a technique for feeding power to an outdoor broadband cabinet is a technique that receives power from the customer premise without using local power in order to increase efficiency of miniaturization and installation of the cabinet.
In the prior art, the power is converted into DC power and transmitted through a wire line in subscriber equipment and the transmitted power is regulated and fed to the broadband equipment of the cabinet again. In addition, when the power is transmitted in the subscriber equipment, the power may be transmitted while being adjusted to the type of power required by the broadband equipment. Therefore, the broadband equipment is supplied with the power adjusted by matching the power required by the broadband equipment of the cabinet with the DC power actually supplied.
However, since the present invention provides the technical configuration that measures the line resistance of a communication line connected to the distribution point at the customer premise and performing the reverse power feeding to the distribution point by reflecting the measured line resistance, the present invention has a clear difference in the technical characteristics from the prior art which proposes only the technical configuration that supplies the power to the cabinet in the subscriber equipment and does not describe the load balancing technique.
The U.S. Registered Pat. No. 7,672,448 (registered on Mar. 2, 2010) which discloses contents regarding a device for supplying power to a network device, a technique that supplies power to a residential gateway positioned outside a home in a remote power supply device positioned in the home by using the existing telephone line.
The prior art proposes a scheme in which since the residential gateway is located in a network interface device (NID) outside the home, there is a problem of power supply and there is an NID device which cannot supply AC power, and as a result, the power is supplied to the residential gateway by a method that sues the existing telephone line instead of installing a new telephone line which is high in cost.
However, since the present invention provides the technical configuration that measures the line resistance of the communication line connected to the distribution point at the customer premise and performing the reverse power feeding to the distribution point by reflecting the measured line resistance, the present invention has a clear technical difference in that the load balancing can be performed with respect to the power feeding to the distribution point at the customer premise from the prior art which describes only the configuration that supplies power to the gateway located outside the home from the remote power supply device located in the home.
That is, most of the prior arts including the above-mentioned prior arts have proposed the configuration in which the power supply unit having multiple interface ports is configured in the DP to balance the power supply of the CPE at the DP, but the load balancing technique of the related art performed at the distribution point is very complicated in execution process and the design of the distribution point is thus difficult, and performing the load balancing itself is difficult when the reverse power feeding to the distribution point at each customer premise is not properly performed, and as a result, has a clear technical difference from a configuration of the present invention in which in which power having a capacity which is averagely similar is supplied to the distribution point by reflecting the line resistance of the communication line at each customer premise, thereby stably supplying the power to the distribution point through the load balancing at each customer premise.